A Glossary of Down Jacket Terms

A Glossary of Down Jacket Terms

This post was created by Triple F.A.T. Goose, an outerwear brand that Travel and Leisure magazine named as a top pick and said, "This is the best goose down winter coat I’ve ever worn" when describing Triple F.A.T. Goose down coats.

Modern down jackets are a sophisticated blend of high tech fabrics, innovative design, and advanced construction techniques. So much so that the terms and ratings used to describe these garments can be quite confusing at times. What is “fill power” and why is it important? What does “DWR” stand for? What’s the difference between “water-resistant” and “waterproof”? Those are simple questions that can seem awfully complicated to consumers, most of whom are simply looking for the best jacket to keep them warm and dry in cold conditions. 

In an effort to make things easier, we’ve collected and defined some of the most common terms that are used to describe the performance of a down jacket and the materials that are used in its construction. By understanding what these terms mean, you should be able to make a more informed decision on what to buy the next time you go shopping for a jacket of your own. 



Arctic Parka:  A parka that has been specifically made to withstand the extreme cold found in polar regions. This style of jacket tends to use the highest fill power down available to provide the most warmth and protection from cold temperatures. The fabrics used in an arctic parka’s construction should also be water and wind-proof, creating a premium coat that offers warmth and protection in extreme temperatures. Arctic parkas will also often feature hoods with fur trim to provide additional warmth while reducing cold air contact to the face.


Baffles:  When two layers of fabric are sewn together, the pocket of space that is formed between those layers is referred to as the baffle. This pocket is put to good use when creating a jacket as it is used to hold down or synthetic insulation in place in order to generate warmth. The two most common types of baffling methods are box baffles and sewn-through baffles.

Base Layer:  The layer of clothing that sits closest to the skin to help wick away moisture and regulate warmth. While base layers can vary in thickness based on the outside temperature, they tend to be lightweight, form-fitting, and stretchy. Examples of base layers include thermals, long johns, and long underwear, all of which play a key role in a proper layering system.

Bomber Jacket:  Based on a style of jackets made popular by pilots during World War II, the bomber jacket (or flight jacket as it is sometimes called) has remained popular for decades. From a design aspect, this type of jacket features a waist-length cut, a ribbed waistband, and matching cuffs. Traditionally, bomber jackets are made from leather although modern versions incorporate an array of more technical fabrics. A zippered front, and four functional pockets on the sides and chest, usually round-out the design of the jacket, giving its own unique style.

Box Baffle:  An approach to baffle construction that creates individual pockets designed to hold the insulating down in place. These individual baffles are lined with a lightweight material that sits between the shell and liner, creating a “box” of sorts. The down is then inserted into that box, which holds it in place, allowing the insulation to provide more warmth where it is needed most. 


Down:  Down is a layer of soft, fine feathers, often referred to as plumage, that is found under the larger, more durable surface feathers of a bird. The material is known to be amongst the best natural insulators, offering a fantastic warmth-to-weight ratio. This makes it a good choice for use as an insulator in jackets, sleeping bags, bedding, pillows, and other products where generating warmth without adding extra bulk is of the utmost importance.

Down used in these products is typically harvested from geese and ducks, mainly as a byproduct of the food industry. In addition to its warmth, down is lauded for being extremely lightweight, highly compressible, and very durable too.

Find out more about what makes down so special by clicking here

Down Parka:  A version of the classic parka that uses down rather than synthetic insulation. Thanks to its efficient design, extended length, and use of goose or duck down, these types of parkas tend to be amongst the warmest on the market. Unlike traditional parkas that were made from fur or animal skin however, the modern down parka features technical fabrics, DWR treatments, and rugged zippers.

Duck Down:  As you’ve probably guessed, duck down comes from ducks. Because the demand for duck in the food industry is so large, duck down is more readily available and comes at a cheaper cost than goose down.

Generally speaking, as duck down is smaller and more fine than goose down, duck down isn’t quite as warm and efficient. With that said, it does still offer one of the best warmth-to-weight ratios of any insulating material on the market.

Durable Water Repellent (DWR):  DWR is a chemical coating that is applied to fabric in order to make the material more water-resistant without impacting its breathability. The DWR treatment is usually applied to the outer shell of a jacket to enhance the jacket's ability to repel moisture such as rain and snow.

It should be noted that DWR coatings can wear out over time, but they can be reapplied at home using a spray or wash. The performance of any durable water-repellent treatment can also be impacted by the buildup of dirt, grime, and oils over time. In order to keep the DWR on your jacket functioning at its highest level, be sure to wash your garments from time to time.

To learn more about the differences between water-resistant, waterproof, and water-repellent, click here


Eiderdown:  Produced by a protected species of Arctic seabirds known as Eider ducks, this type of down is amongst the rarest and most expensive on the market. The birds pluck the down from their own bodies and use it to make a nest for their eggs. The warm feathers help to keep the eggs—and later the ducklings—well protected in the cold climates found above the Arctic Circle. After the birds abandon their nests, the down is collected by hand for use in jackets and other products. Only about 5000 pounds of the material is harvested worldwide on an annual basis, which is why it is sold at such a premium price.

Learn more about Triple F.A.T. Goose, a brand with a 35 year history that has been featured in Outside, Esquire, Vogue, Elle, Men's Journal, Cosmopolitan, Robb Report, and more. All Triple F.A.T. Goose coats have a fill power rating of 675 and up. Shop the collection.



Fill Power:  The “fill power” (or “fill rating”) of a down jacket is an indicator of the quality of the down used in a garment. This number is a representation of the loft of the down, which is determined by measuring how many cubic inches of space that the down occupies at its highest level of loft. For example, an ounce of down with a fill rating of 800 would cover approximately 800 cubic inches. When considering fill power ratings, higher numbers are better. 

This rating system differs slightly in the U.S. as compared to Europe. That difference comes down to the size of the plexiglass container that is used to measure the loft of the down during testing. The one that is used in America is slightly smaller in size, which is enough to cause fill power numbers to skew about 7-8% higher in the U.S. 

Learn more about fill power ratings by clicking here.

Fill Ratio:  While down is used as the primary insulator in a jacket, oftentimes feathers are used as a filler. The fill ratio is an indicator of just how much down has been used versus those feather fillers. This is expressed as a number such as “80/20” or “90/10”, with the first number indicating the percentage of down and the second number indicating the percentage of feathers. The higher the ratio of down to feather, the higher quality—and warmer—the jacket will be. 

Discover more about the importance of fill ratio by clicking here.

Fill Weight:  The fill weight (or “down weight”) of a jacket is a measurement of the actual weight of the down used in the production of that garment. This means that a fill weight of 8 ounces indicates that 8 ounces of down were used as insulation. This number functions independently of fill power, indicating weight but not necessarily warmth.

You can find out more about how fill power and fill weight differ by clicking here.

Fur Ruff:  A reference to the fur—real or fake—that runs along the brim of the hood of a parka. Sometimes referred to as the fur trim, this material helps keep the face warmer by preventing cold air from reaching the interior of the jacket.


Goose Down:  Unsurprisingly, goose down is the down that comes from geese. Because these birds are larger and more adapted to living in cold climates, the down tends to be larger and thicker as well when compared to duck down. This also makes it a more efficient insulator, which when combined with its lower supply, can make products that use goose down a bit pricier.

Gray Down:  Down that is gray in color is considered to be lower in quality than white down. Gray down is not recommended to be used on light-colored or thin fabrics as the gray down color may show through the fabric.


Hand-warming Pockets:  The pockets on a jacket that are specifically designed to keep the wearer’s hands warm. These pockets are usually located on both sides of the jacket and are often lined with fleece or similar material in an effort to add additional warmth.

Hard Shell:  This term is used to describe the type of fabric used as the outer layer of a jacket. A hard shell tends to offer very little in terms of stretch and flexibility, substituting those qualities in favor of durability and waterproofing instead. Most hardshell jackets will feature a DWR coating and seam-sealed construction, offering outstanding protection from the wind, rain, and snow.

Heat Sealing:  A method of seam sealing that uses heat to “weld” two pieces of fabric together in an effort to improve waterproofing. The process seals shut the tiny holes that are created along the seams when the materials that make up a jacket are stitched together, keeping wind and moisture out as a result.

Read more about seam sealing and waterproof jacket construction here.

Hutterite Down:  This type of down derives its name from the Hutterite people, a small ethnic group that occupies rural communities throughout the northwest U.S. and Canada. Hutterite down can come from booth geese and ducks, and because those birds are allowed to grow to their full maturity without the use of growth hormones, it tends to be thicker and fuller. This makes it a more efficient option for use as an insulator. Because of the long maturation process and limited supply, Hutterite down comes at a premium.

Hydrophobic Down:  Developed to improve down’s performance in wet conditions, hydrophobic down has been treated with a special durable water repellent (DWR) coating that allows it to repel moisture. This gives it the ability to maintain its loft even when wet, preserving its ability to serve as an insulator. 

Hydrostatic Head Test:  A measurement of how much water pressure a fabric can withstand before becoming saturated, the Hydrostatic Head Test determines a material’s level of water-resistance. The test is conducted by using a double open-ended cylinder, which is placed atop a piece of fabric. The cylinder is then filled with water, which then seeps into the material over time to determine how much moisture can absorb before it becomes saturated. The results are measured in millimeters, with a higher number indicating more effective waterproofing. 

To learn more about the hydrostatic head test and the differences between water-resistant, waterproof, and water-repellent, click here.


Lightweight Down Jacket:  Designed for use in mild weather rather than extreme conditions, a lightweight down jacket uses thinner fabrics and less down to create a slimmer and lighter garment. These types of jackets tend to be highly compressible and also work well as part of a layering system that uses multiple layers of clothing to generate warmth. 

Loft:  The term loft is commonly used when describing down. It is typically a reference to the fluffiness of down and is often used interchangeably with its fill rating. By the simplest of terms, down that has more loft is warmer and is of a higher quality. It also occupies more space, meaning that less down is needed to fill a jacket, sleeping bag, or comforter.


Mid-Layer:  Any layer of clothing that sits between a base layer and an outer layer. Typically, this is referred to as the “insulating layer” adding additional warmth when needed. Traditional mid-layers can include everything from fleece pullovers, sweatshirts, sweaters to long sleeve shirts, or even a lightweight down jacket depending on the conditions. 

Midweight Down Jacket:  Falling between a lightweight down jacket and a down parka, this type of coat looks to find a balance between warmth, compressibility, and performance. Typically, a midweight down jacket uses down that has a high fill power at a high fill ratio, creating a coat that can be used in typical winter conditions. 


Outer Layer:  Designed to protect the wearer from wind, rain, snow, and the cold, the outer layer is typically a weatherproof shell jacket or an insulating layer such as a parka. The purpose of this layer is to provide additional warmth while keeping moisture at bay and remaining breathable. The outer layer is the first level of protection from the elements, and the most important, especially in extreme cold.


Packable Down Jacket:  A down jacket that is specifically designed to be compressible enough for easy transport and storage. This is typically achieved by using high-loft down, but at a low fill weight. This, combined with thinner shell fabrics, results in a lightweight jacket that takes up less room in a piece of luggage or backpack, making it an excellent choice for travel.

Parka:  A parka is the name of a style of coat that was created by the Caribou Inuit people of northern Canada. Originally made from caribou or seal skin, the jacket traditionally features an open front that makes it easy to slip on and off as needed. A parka is also long enough to drop below the waist, usually reaching to mid-thigh or even knee-length. An oversized, fur-lined hood is also a trademark feature of this style of coat. Unlike traditional parkas that were made from fur or animal skin, modern parkas will often feature technical fabrics, DWR treatments, down insulation, and rugged zippers.

Puffer Jacket:  This is a commonly used term for a down jacket, which typically features a quilted design that can appear “puffy” due to the abundance of down or synthetic insulation. That insulation is placed inside the pockets of fabric that are created through the quilting process, trapping warm air and keeping the wearer of the jacket warm as a result. Puffer jackets, which are sometimes referred to as “puffers” for short, tend to be lightweight, highly compressible, and very warm.


Seam Sealing:  A technique used to increase the waterproofing on a jacket by sealing the small holes that are made during the construction process. When a jacket is made, the materials are stitched together using a needle, creating hundreds of tiny holes where the thread binds the layers of fabrics together. If those holes aren’t sealed in some way, moisture can seep into the interior of the garment, greatly diminishing its effectiveness as a protection against the elements.

Seam Sealing Tape:  A multilayered adhesive film or fabric that is used along the seams of a jacket to seal the holes created when stitching materials together. When applied to those seams, the tape prevents moisture from reaching the inside of the jacket, thereby increasing its waterproofing. 

Sewn Through Baffle:  With this type of baffle, the lining of the jacket is sewn directly to the shell and the down insulation is inserted between those two layers. Because no additional materials are used in the construction of a sewn-through baffle—as it is with a box baffle—this approach usually provides a lighter-weight garment. 

Soft Shell:  A term used to describe the outer layer of fabric found on a jacket. Typically lightweight, and highly breathable, the materials that fall under the heading of a soft shell are comfortable, stretchable, and designed to not inhibit motion. This makes them ideal for use in high-energy activities such as climbing or running. 

Storm Cuffs:  An inner cuff on a jacket that is designed to keep wind, rain, and snow at bay. Usually made of elastic, or a similarly stretchable material, the storm cuff is designed to fit snugly, providing extra protection from the elements. 

Synthetic Down:  Synthetic down is a manmade substitute for natural down that is produced under several different names and brands, including PrimaLoft, Thinsulate, and Polartec. This type of insulation has been specifically engineered using polyester to mimic down’s ability to capture and hold body heat for added warmth. Other benefits include better performance in wet conditions, costing less to produce, and having hypoallergenic properties too. However, synthetic down doesn’t tend to be as warm as natural down, nor is it as compressible or durable either.


Temperature Rating:  Developed to assist consumers in understanding how well a jacket performs in cold weather, the temperature rating (or temperature range) provides a rough estimate of expected warmth. The rating is meant to indicate at which temperature the jacket performs best, although it doesn’t typically consider such variables as wind, rain, humidity, or level of physical activity. Those factors can have a dramatic impact on comfort, which means temperature ratings aren’t always a good indicator of overall performance. 

For more information on the accuracy and reliability of temperature ratings, click here.

3-in-1 Jacket:  A versatile style of jacket that includes two layers that can be connected to one another in order to create a warmer, more protective garment. Either of those two layers can be worn independently from one another, essentially providing three jackets in a single design. Typically, the outer layer is a wind and waterproof shell designed to protect the wearer from the elements. Conversely, the inner layer usually incorporates fleece or down insulation to create a warmer jacket instead. When the two independent layers are zipped or snapped together, they form a single jacket that combines all of these qualities together.

2 Layer Fabric:  One of the more common construction methods for waterproof and breathable fabrics, a two-layer design applies a laminate or membrane to a face fabric without attaching any other material to the interior. When incorporated into a jacket, a lightweight mesh or porous fabric is added to the inside to serve as a liner. This is a cost-effective way of designing a waterproof jacket, but it also tends to add additional weight to the final product. 

Learn more about the 2 Layer, 2.5 Layer, and 3 Layer fabrics and how the best rain jackets are made here.

2.5 Layer Fabric:  A step up in performance from a two-layer fabric, this type of material adds a polyurethane laminate to the inside of a jacket. This coating isn’t a true layer, which is why it is labeled a half-layer instead. But, it does enhance performance by protecting the fabric from dirt, mud, sweat, and oils that could block the microscopic pores that allow it to breathe and vent excess heat. 2.5-layer jackets tend to be more lightweight than other styles, which can lead to lower levels of durability. They also need to be cleaned regularly in order to keep them performing at their highest level. 

Learn more about the 2 Layer, 2.5 Layer, and 3 Layer fabrics and how the best rain jackets are made here

3 Layer Fabric:  As the name suggests, this type of material incorporates three independent layers that are used in the construction of the jacket’s shell. The outer layer is made up of material that includes a laminated DWR coating, which is bonded to a waterproof—yet breathable—membrane that serves as the second layer. A polyurethane film or lining acts as a protective third layer, keeping dirt and sweat from blocking the pores of that membrane. All three layers bring distinct features to the table, creating a high-performance fabric in the process. 

Examples of coats that use 3-layer fabrics include the men’s Huron and Valen, as well as the women’s Ellaria and Chelsea.

Learn more about the 2 Layer, 2.5 Layer, and 3 Layer fabrics and how the best rain jackets are made here.


Ultralight Down Jacket:  A type of down jacket that puts an emphasis on staying as lightweight as possible. Often weighing just a few ounces, these jackets achieve their svelte design through the use of high fill power and high fill ratios, but with a low fill weight. The outer shell fabrics of an ultralight jacket also tend to be thin and lightweight too, creating a product that is highly compressible and weighs next to nothing. However, because the outer shell fabric is ultra-lightweight and thin, it is not very durable.

Underarm Vents:  Designed to release excess heat and enhance airflow through a jacket, underarm vents can play a crucial role when it comes to staying comfortable. The vents vary in length, but typically start somewhere along the sleeve, run up to the underarm, then down the torso. Zippers or Velcro tabs allow the vents to be opened or closed as needed. 


Warmth-to-Weight Ratio:  A measurement of the level of warmth that a type of insulation offers as it relates to how much that insulation weighs. For example, down has a very high warmth-to-weight ratio because it is extremely lightweight, yet also very warm. This makes it ideal for use in jackets and sleeping bags that can keep us comfortable in cold conditions without adding additional bulk to a backpack. 

Water-Repellent:  Water-repellency is a characteristic of water-resistant and waterproof fabrics that allows it to shed moisture upon contact. In other words, as soon as water hits the surface of the material, it starts to bead up and is “repelled” in a quick and efficient manner, keeping any inner layers as dry as possible. Most fabrics gain the ability to repel water thanks to a durable water repellent (DWR) coating or a layer that can be integrated into the fabrics themselves or added to the surface during production. 

To learn more about the differences between water-resistant, waterproof, and water-repellent, click here

Water-Repellent Zippers:  A zipper that has been specifically designed to ensure that little or no moisture reaches the interior of a jacket. Unlike standard zippers—which usually allow water to pass through—water repellent zippers are seam-sealed around the edges and made from materials designed to keep moisture away. The result is a better seal that enhances the performance of a waterproof jacket even further. 

Water-Resistant:  When a product is rated as “water-resistant’ that means that it has been designed to keep the user dry from brief or light amounts of moisture. Typically that means a steady mist, light rain, or snow flurries. These products are generally not capable of withstanding prolonged exposure to heavy rainfall or snow showers. 

From a more technical standpoint, the Hydrostatic Head Test requires that water-resistant fabrics be able to withstand water pressure of 1500 mm or more. 

To learn more about the differences between water-resistant, waterproof, and water-repellent, click here.

Waterproof: When a garment earns a “waterproof” rating it means that it is capable of withstanding much higher levels of exposure to moisture as compared to one that is only rated as “water-resistant.” In this case, the fabrics are able to prevent any moisture from soaking through under all but the absolute worst of weather conditions. 

In order to earn a waterproof rating, a down jacket generally needs to have its outer shell treated with a durable water repellent (DWR) coating or laminate that is capable of shedding moisture at a rate of 10,000+ mm or more. Additionally, the materials used to create that jacket need to increase that level of protection even further, including using water repellent zippers and hydrophobic fabrics. Finally, the jacket should be constructed with seams that have been sealed in some fashion to prevent moisture from reaching the interior as well, providing extra protection as a result.

To learn more about the differences between water-resistant, waterproof, and water-repellent, click here

White Down: A direct reference to the actual color of the down, white down is considered to be the highest quality down available due to its clean look and color. Because of this, it tends to cost a premium over gray down.

White down is recommended to be used with all types of fabrics and colors.

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